Aiming at the problems of low power load and difficult charging in rural areas, this paper puts forward the strategy of constructing integrated optical storage and charging station in rural areas, and introduces the concrete application methods of the strategy.
The results show that the construction of optical storage and charge integrated charging stations in towns can significantly improve the efficiency of electricity consumption, and can reduce investment costs and operating costs.
The importance of building integrated optical storage and charging station
As the number of electric vehicles is increasing, the demand for charging is increasing. If it is not properly managed, it will lead to a large amount of waste of electric energy in the charging process of electric vehicles, and then bring great pressure to our power system. The construction of optical storage and charging integrated charging station can effectively solve the above problems.
The integrated charging station is a new charging station mode, which applies photovoltaic power generation and energy storage technology to the charging station to provide a good solution for electric vehicle charging.
In this mode, photovoltaic power generation can be directly transmitted to the charging station through grid-connected, and then by charging the battery can provide electricity for electric vehicles; Energy storage technology is the use of energy storage equipment dispersed in the grid, when the user needs to provide electricity to the grid. Compared with the traditional charging station, the optical storage and charging integrated charging station can effectively improve the operational efficiency of the power system.
The integrated charging station of optical storage and charging can effectively reduce the electric charge cost and operation cost during the charging process of electric vehicles.
Under this model, PV and energy storage systems will continue to operate until the grid runs out of electricity, and the charge generated during the charging process of electric vehicles will be covered by integrated charging stations.
For users, this model can not only save costs, but also effectively reduce energy waste. In the actual operation process, the optical storage and charging station can achieve the maximum economic and social benefits by optimizing the configuration and scheduling management.
Therefore, it can be said that optical storage and charging integrated charging station is a new type of charging station with good prospects for development.
Analysis of current situation of power grid construction in rural areas
Power grid construction in township areas
At present, our country's rural area power grid is still in the stage of the traditional power grid structure-based, mainly with overhead lines, distribution network automation, digitalization and other modern technology application is insufficient, most towns and villages are still without electricity. There are five problems in the construction of power grid in rural areas of our country.
1). The low level of distribution network automation in some villages and towns, the imperfect distribution network automation system, and the lack of real-time monitoring and early warning of distribution network operation, seriously affect the normal operation of distribution network automation system in villages and towns.
2). The distribution line supply radius is larger in some rural areas, which makes the distribution line unable to shorten the supply radius effectively.
3). The structure of distribution network in some rural areas has serious aging phenomenon, and some distribution lines even have problems such as small conductor cross section, small wire diameter and equipment aging.
4). There are some problems in reactive power compensation configuration in some rural areas, such as insufficient equipment capacity and reactive power compensation capacity.
5). The power supply enterprises in some villages and towns lack scientific and reasonable management mechanism, planning and design idea, and analysis and prediction of power consumption on the user side.
The energy structure of the township area
The energy structure in rural areas is characterized by high pollution, high energy consumption and low efficiency.
With the rapid development of China's economy, People's living standards continue to improve, the demand for energy is also increasing, a large number of fossil energy consumption, resulting in increasing environmental pollution.
In recent years, the energy structure in rural areas has been optimized and upgraded, and the utilization level and quantity of clean energy have increased obviously.
1). The load capacity of rural areas is small, and the residents in rural areas have low power consumption and mainly use low-power electrical appliances.
2). The number of electric vehicles (EVS) in rural areas is increasing. EVS are mainly driven by electric energy, and use the electric power system to provide auxiliary energy. The increase in the number of EVS will inevitably result in an increase in the electric load.
3). The structure of power supply in rural areas is unreasonable. Due to the low electricity consumption, the single power supply structure and the lack of scientific and reasonable planning and design, it is difficult to meet the electricity demand in rural areas.
4). There is serious overload in rural area, some of which have the problems of low voltage and aging line, which seriously affect the safe and stable operation of power system.
Power quality of distribution network in township area
Power quality is one of the important factors that affect the quality of life of rural residents, and it is also one of the main problems that electric power enterprises must solve. At present, the power quality of distribution network in rural areas is mainly faced with the following three aspects of the problem.
1). The voltage deviation of rural power network is large, and the voltage of some users appears negative deviation.
2). The unbalance degree of three-phase voltage of distribution network in some villages and towns is beyond the range of national standard.
3). There are serious three-phase unbalance phenomena in distribution network in rural areas, which lead to the problem of power quality on user side.
Case study on the construction of integrated optical storage and charging station
In order to better promote the economic development of rural areas, the state vigorously promotes the construction of new energy charging stations. At present, there are still some problems in the construction of new energy charging stations in our country, for example, the location of charging stations difficult, low utilization of charging facilities, low charging efficiency.
To this end, our country began to accelerate the construction of electric vehicle charging stations. In order to solve the problem of electric vehicle charging in rural areas, the integrated charging station of optical storage and charging can be built in rural areas.
The integrated charging station consists of three parts: photovoltaic power generation system, energy storage system and charging station. In the process of construction, it is necessary to build the photovoltaic power generation system first, and then use the energy storage system to manage the charging of electric vehicles.
In addition, it is necessary to set AC charging post and DC charging post in charging station to provide convenience for electric vehicle charging.
On the whole, the economic development level of rural areas is relatively low, so the cost of building optical storage and charging integrated charging stations is relatively low. Taking a township as an example, the economic level of the township is in the middle level in the country, and the construction of integrated optical storage and charging station can achieve good economic benefits.
1). The town itself has sufficient light resources and land resources, which can be fully utilized to build the integrated charge station of light storage and charging.
In the design of integrated optical storage and charging station should first choose the appropriate building materials and structural form, and then combined with the local geographical location and climate conditions to design.
For example, the town because of the cold climate, sufficient light, land resources are relatively more, you can choose photovoltaic panels to build integrated storage and charging station.
2). The PV system is mainly responsible for charging electric vehicles, while the energy storage system is responsible for storing the electricity. The PV system and the energy storage system should be combined in a reasonable way during construction.
In addition, it is necessary to reasonably set the capacity and quantity of energy storage battery and storage battery in the energy storage system. The battery capacity should be set according to the charge demand of electric vehicle. In general, the battery capacity can be determined according to the use situation, location and market demand of electric vehicle. On this basis, the charging time and charging efficiency of electric vehicle should be designed reasonably.
3). The optical storage and charging integrated charging station also needs to reasonably configure the various equipment of the charging station.
In the construction of the integrated charge station should try to choose good quality, stable performance of equipment to avoid equipment failure and affect the normal operation of the charging station.
In addition, the intelligent management of optical storage and charging integrated charging station can be realized by improving the intelligent degree of charging station.
4). After the construction of the integrated charging station, it is necessary to carry out the acceptance and trial operation of the station:
① It should be in line with the national standards and industry standards for acceptance;
② Whether its construction conforms to the local policy requirements and user requirements for acceptance;
③ It should be accepted for its normal operation. The trial operation mainly includes the following two aspects: ① Whether the charging station conforms to the charging standards and related norms should be tested; ② Whether the charging station conforms to the safety regulations and related standards should be tested.
Optical storage and charging integrated charging pile capacity configuration
The charge time of electric vehicle is mainly affected by the power and charge time of electric vehicle, that is, the charge time of battery and charge time of electric quantity.
Therefore, it is necessary to estimate the charging time according to the power of electric vehicle. At present, there is no unified standard for charging piles in our country, and the charging time of charging piles of different brands is quite different, so we can use some methods to estimate the charging time of charging piles. The charging piles were classified according to 4H, 12h and 16h respectively.
According to the above method, the charging time of the charging pile can be estimated, and the charging time of the charging pile with different capacity configuration can be obtained. In the capacity allocation of charging piles, we should also fully consider the characteristics of rural residents and electric vehicle charging needs.
Different voltage levels of electric vehicles require different power, so according to the needs of the charging station equipment configuration.
Under normal circumstances, rural residents with voltage levels of 220V and 110V, so in the construction of charging stations need to be equipped with the corresponding voltage levels of charging piles.
Take Anhui province as an example, under normal circumstances, rural residential voltage levels of 10 kv and 35 kv. With the increase of electric vehicle power and the reduction of charging time, the average charging time will gradually decrease.
Integrated Optical Storage and charging station project
Economic benefit analysis
The integrated charging station with 4 kinds of power is 120kW, 250KW, 400kW and 600kW. It is found that the internal rate of return is 10.24% and the payback period is 3.65 years when the power is 120kw.
Due to the small number of electric vehicles and the low charge demand in our country, we can choose the small capacity project to construct the integrated charge station, in order to meet the current rural areas of electric vehicle charging needs.
Construction of integrated optical storage and charging station
Technical difficulties and solutions
The following technical difficulties need to be solved for the further development of integrated optical storage and charging stations in rural areas.
1). The design and construction of user-side energy storage system. The design and construction of the user-side energy storage system is the key to the construction of the integrated optical storage and charging station in rural areas.
2). The coordinated control of photovoltaic power generation system and charging system. It is necessary to fully consider the coordination and control between the photovoltaic power generation system and the charging system when constructing the integrated charge station in rural areas. The coordination control between photovoltaic power generation system and charging system mainly includes two aspects:
On the one hand, it is the coordinated control between the photovoltaic power generation system and the energy storage system, on the other hand, it is the coordinated control between the photovoltaic power generation system and the charging system.
Charge and discharge controller, power regulator and other devices can be used to coordinate the control between photovoltaic power generation system and energy storage system.
When the output power of the photovoltaic power generation system is insufficient, the excess power can be replenished to the charging station in time by the charge and discharge controller, the power regulator can be used to reduce the photovoltaic generation capacity, thereby avoiding overcharging.
In addition, the super capacitor can be used to achieve the charging function of photovoltaic power generation equipment.
3). Charging station grid-connected control strategy. Under normal circumstances, small-scale power grids in rural areas lead to grid-connected instability. In order to ensure the safety of power consumption in rural areas, a large number of distributed power supply in power grid should be controlled and managed by grid-connected controller.
At the same time, the distributed power supply can be connected to the power grid through the grid-side converter.
In addition, it is necessary to make use of battery, super capacitor and other devices to achieve the coordinated control of distributed power supply.
4). Power distribution control design of charging station. In general, when the user-side energy storage capacity is insufficient, the excess power can be added to the charging station through a bi-directional converter, and when the user-side energy storage capacity is sufficient, the use of super-capacitors can be used to charge and discharge the photovoltaic power generation equipment.
5). The operation maintenance and management of optical storage and charge integrated charging station. Specifically, it includes the following seven aspects: ① To formulate a sound work plan; ② To strengthen the training of relevant personnel; ③ to regularly inspect and maintain the equipment; ④ To establish and improve the charging station Operation Management System; ⑤ To regularly organize and carry out various training activities; ⑥ To establish and improve the charging station operation and maintenance mechanism; ⑦ To deal with equipment failure in a timely manner, etc.
This paper analyzes the technology and economy of the photovoltaic power generation and energy storage projects, and draws a conclusion that it is feasible to build the integrated charging station in rural areas.
The scheme has good economic and social benefits, and meets the requirements of the development of new energy power generation industry under the“Double carbon” target in China. With the continuous progress of new energy generation technology, photovoltaic power generation technology will be more widely used, energy storage technology will also be more widely used.
Therefore, our country should increase the research on advanced new energy generation technologies such as new energy storage technology and photovoltaic power generation technology to provide more support for the development of new energy power generation industry.
